Intracranial hemorrhage (ICH) is a major public health problem with the highest mortality rate of all stroke subtypes and long-term disability, and has no available FDA-approved therapies. Although the number of hospital admissions for intracranial hemorrhage has increased worldwide, mortality has not fallen. ICH causes instantaneous mass effect, disruption of surrounding brain, and often an early neurological death, and in case of subarachnoid hemorrhage delayed cerebral ischemia (DCI) and cerebral vasospasm. Intracranial hemorrhage (ICH) occurs when blood leaks or bursts from broken/diseased blood vessels inside or on the surface of the brain leading to brain damage and neurological damage. Following ICH, the deposited blood is damaging initially via compression of the brain tissue (mass effect) and then via noxious chemical effect of hematoma components on brain (including vascular) tissue. Blood deposition leads to toxicity of hemolytic products (e.g., iron), oxidative stress, pro-inflammatory responses, immune cell recruitment, proteolytic enzymes-mediated extracellular matrix modification, blood brain barrier disruption, and deadly cerebral edema. Due to multifactorial nature of the disease, specific therapies for ICH treatment have been elusive. Since there are no available therapies for ICH there is a longstanding and unmet need for an effective treatment.
Lactoferrin (LTF) also known as lactotransferrin, is a well-known endogenous glycoprotein that is multifunctional with anti-microbial and immunoregulatory functions capable of curbing the inflammatory response and promoting repair, in part through its effective sequestration of free iron as LTF falls within the transferrin family of iron binding glycoproteins. Lactoferrin is a well-conserved, monomeric 80-kDa single polypeptide chain glycoprotein of about 692 amino acid residues that is widely represented in various secretory fluids, such as milk, saliva, tears, bronchial, nasal secretions, intestinal secretions and also in the secondary granules of neutrophils. Lactoferrin is also present in secondary granules of granulocytes (polymorphonuclear leukocytes; PMNs) and is secreted by some acinar cells. Lactoferrin may be purified from milk or produced as a recombinant protein. Lactoferrin is a critical component in mediation of immune response, especially for coordinated interactions between innate and adaptive components and associated responses. Engagement of innate components leads to triggering of signal pathways to promote inflammation, ensuring that invading pathogens remain in check while the specific immune response is either generated or upregulated. Lactoferrin is a key molecule involved in these processes.
Lactoferrin is a well-conserved, monomeric 80-kDa single polypeptide chain glycoprotein organized in two highly homologous lobes, designated the N- and C-lobe, each capable of binding single ferric ion (Fe3+). In this regard, lactoferrin is considered an antioxidant because its iron binding ability inhibits the iron-catalyzed formation of H2O2 and .OH. Ultimately, lactoferrin bound Fe3+ is safely transported to the macrophage or other cells for intracellular utility or storage. LTF has also been implicated in immunoregulatory functions, with modulatory component in allergic responses and protection against insult-induced mitochondrial dysfunction.
Lactoferrin is also a well-known endogenous glycoprotein with anti-microbial and immunoregulatory functions, capable of curbing the inflammatory response and promoting repair through its effective sequestration of free iron. However, LTF has limited therapeutic potential because of its short half-life in the blood and its difficulty penetrating the blood-brain barrier.
LTF is therefore rapidly cleared from the circulation (half-life of a few minutes). Therefore, despite the various activities ascribed to lactoferrin, there remains a need for the development of an efficient lactoferrin construct that provides a robust therapeutic for the treatment of a mammal.
Recently lactoferrin fusion proteins have thus been disclosed in the prior art such as described in PCT/JP2013/062685, and US patent publication US20150093382, however, there is a need to further optimize endogenous LTF, and such fusion proteins to improve cognitive processes and neurological functions, as well as change cellular responses in the area of damage, such as the anti-inflammatory responses of microglia, reduced infiltration of neutrophils, and lowered extent of neuronal death.